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Old 07-16-14, 11:52 AM   #1
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Question eBike diagnostic help

About 2 years ago I converted my Easy Racer recumbent to an E bike with a kit off of eBay from Hong Kong. It has now died. I bought the kit off of eBay, and the Hong Kong vendor has vanished. I tried to track them down and actually had a Chinese friend in China call them. They gave him all the polite words but then stopped answering their phone after that. I need some help with diagnostics and buying whatever replacement parts are necessary to get it going again.

I have a 20 amp hour lithium-ion battery with 54+ volts coming out of the associated BMS. The the 1000 W motor is integrated into the back wheel. The thing was running really well, like it would cruise at 45. It cut out temporarily a couple times then died totally. I have no power to the headlight, key switch, horn, throttle lever or battery level LEDs. I have checked all of the connections. My suspicion is that the problem is in some of the controlling circuitry on the handlebars, but I don't have a clue about how to go about diagnosing the exact source of the problem.

Though it looks well designed and built, there are no brand names on any of the parts. The only brand name anywhere is SENYUAN on the headlight. I will be glad to supply photos and any additional information if that would be helpful.

I have a fluke 77 multimeter.

The output from the charger is 60 V. Most of the stuff on the battery charger is in Chinese, but in one spot it says 48V

The only markings on the battery are that on the sticker... Battery-BMS.jpg

There are no signs of overheating of the BMS or the controller.

I have repeatedly checked all of the connections

Two views of the controller are also attached.
controller-Label.jpg is a closeup of the label on the controller

If this were a battery problem but still pumping 53.4 V would not the bike attempt to move or the control lights come on. it suddenly went from running great to totally dead. there was no degradation in performance except suddenly from 10 to 0

There are 2 plugs, one with seven and one with eight wires, for a total of 15. eBikeBattery.JPG
shows how I am measuring the values below.

measured V cell V
to each wire
1= 3.6 3.6
2= 7.2 3.6
3= 10.8 3.6
4= 14.3 3.5
5= 17.9 3.6
6= 21.5 3.6
7= 25.2 3.6
8= 28.7 3.5
9= 32.5 3.8
10= 35.9 3.4
11= 39.4 3.5
12= 43.1 3.7
13= 46.6 3.5
14= 50.4 3.8
15= 54.0 3.6

16. = 53.7 controller input
17. = 53.6 controller output

I would appreciate it if someone could guide me through the diagnostic process or refer me to a vendor who could. I'm in Spokane Washington.

Thanks Larry
Attached Images
File Type: jpg eBikeBattery.JPG (61.9 KB, 1 views)
File Type: jpg Battery-bms.jpg (95.9 KB, 1 views)
File Type: jpg Battery-BMS2.jpg (103.1 KB, 1 views)
File Type: jpg Controller.JPG (81.5 KB, 1 views)
File Type: jpg Controller2.JPG (88.5 KB, 1 views)
File Type: jpg controller-Label.jpg (77.4 KB, 1 views)

Last edited by docweathers; 07-16-14 at 12:00 PM. Reason: fix formatting
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